Just these past few months, I have been running approximately 3km every night for ankle and knee rehab. But I've been having an annoying chest pain (located on my right side underneath my Pectoralis). As running intensity increases I end up having to stop even though I feel like I could carry on!

The pain usually starts 10 minutes into running on the flat, and will get unbearable if I increase the pace to a sprint. Similar to this, If I run up stairs or an incline the pain comes on in about 30 seconds to 2 minutes and usually makes me stop.

The weird thing about it is I'm able to do any other exercise at a very high intensity without any chest pain (Eg. Bicycle sprints and Parkour).

I have been looking for the source of my pain but have not found anything conclusive. My lecturer suggested it could be an issue with breathing and chest tension/shoulder tension but as I experimented with that it didn't seem to change anything.